Downhole tools having activation members for moving movable bodies thereof and methods of using such tools

Abstract

Expandable reamers for enlarging wellbores include a tubular body and one or more blades configured to extend and retract. A sleeve member within the tubular body has open ends to allow fluid to flow therethrough. A fluid port extends through a wall of the sleeve member. A restriction member within the sleeve is movable between first and second positions. In the first position, fluid flow through the downhole end of the sleeve is generally unimpeded, and fluid flow through the fluid port is generally impeded. In the second position, fluid flow through the downhole end of the sleeve member is generally impeded, and fluid flow through the fluid port is generally unimpeded. The restriction member may be configured to move responsive to changes in the rate of fluid flow through the sleeve member. Methods of using such reamers are also disclosed.

What is claimed is: 
     
       1. A downhole tool for use in forming a borehole in a subterranean formation, comprising:
 a tubular body; 
 at least one movable body carried by the tubular body, the at least one movable body configured to move between an activated position and a deactivated position; 
 a sleeve member disposed at least partially within the tubular body, the sleeve member comprising an elongated cylindrical wall having open ends allowing fluid to flow through the sleeve member, the elongated cylindrical wall having at least one fluid port extending therethrough; and 
 at least one movable restriction member disposed within the sleeve member, the at least one movable restriction member being movable between a first position in which fluid flow through the sleeve member between the open ends thereof is generally unimpeded and fluid flow through the at least one fluid port extending through the elongated cylindrical wall of the sleeve member is generally impeded, and a second position in which fluid flow through the sleeve member between the open ends thereof is generally impeded and fluid flow through the at least one fluid port extending through the elongated cylindrical wall of the sleeve member is generally unimpeded, the at least one movable restriction member being biased toward the first position, the at least one movable restriction member configured to move substantially completely to the second position when a flow rate of fluid through the sleeve member between the open ends thereof meets or exceeds a threshold flow rate, wherein the at least one movable body is configured to move between the activated position and the deactivated position responsive to movement of the at least one movable restriction member between the first position and the second position. 
 
     
     
       2. The downhole tool of  claim 1 , wherein fluid pressure within the sleeve member rises responsive to movement of the at least one movable restriction member from the first position to the second position. 
     
     
       3. The downhole tool of  claim 2 , wherein the at least one movable body is configured to move from the deactivated position to the activated position responsive to the rise in fluid pressure within the sleeve member resulting from movement of the at least one movable restriction member from the first position to the second position. 
     
     
       4. The downhole tool of  claim 3 , further comprising a push sleeve disposed within the tubular body and coupled to the at least one movable body, the push sleeve configured to move responsive to the rise in fluid pressure within the sleeve member resulting from movement of the at least one movable restriction member from the first position to the second position. 
     
     
       5. The downhole tool of  claim 1 , wherein the threshold flow rate is at least about 900 gallons (3406.8 liters) per minute. 
     
     
       6. The downhole tool of  claim 5 , wherein the threshold flow rate is about 1200 gallons (4542.4 liters) per minute or less. 
     
     
       7. The downhole tool of  claim 1 , wherein the at least one movable restriction member comprises a metal. 
     
     
       8. The downhole tool of  claim 1 , wherein the at least one movable restriction member has an arcuate shape. 
     
     
       9. The downhole tool of  claim 8 , wherein the at least one movable restriction member has a partially cylindrical shape. 
     
     
       10. The downhole tool of  claim 1 , wherein the at least one movable restriction member has a generally circular or elliptical peripheral edge. 
     
     
       11. The downhole tool of  claim 1 , wherein the at least one movable restriction member is attached to the sleeve member by at least one hinge. 
     
     
       12. The downhole tool of  claim 1 , wherein the at least one movable restriction member is biased toward the first position by at least one spring. 
     
     
       13. The downhole tool of  claim 1 , further comprising at least one cutting element attached to the at least one movable body, the at least one cutting element projecting laterally beyond an outer surface of the tubular body when the at least one movable body is in the extended position, the at least one cutting element being recessed below the outer surface of the tubular body when the at least one movable body is in the retracted position. 
     
     
       14. The downhole tool of  claim 13 , wherein the downhole tool comprises an expandable reamer apparatus. 
     
     
       15. The downhole tool of  claim 14 , wherein the at least one movable body comprises a plurality of blades. 
     
     
       16. A method of using a downhole tool in forming a borehole in a subterranean formation, comprising:
 flowing fluid through a sleeve member disposed within a tubular body of the downhole tool at a first flow rate below a threshold flow rate; 
 increasing the flow rate from the first flow rate at least to the threshold flow rate to cause the fluid flowing through the sleeve member to move at least one movable restriction member disposed within the sleeve member from a first position to a second position in which the at least one movable restriction member restricts the flow of fluid through the sleeve member; 
 increasing a pressure of fluid within the sleeve member responsive to restriction of the flow of fluid through the sleeve member by the at least one movable restriction member; and 
 moving at least one movable body of the downhole tool from a deactivated position to an activated position responsive to the increase in the pressure of the fluid within the sleeve member. 
 
     
     
       17. The method of  claim 16 , further comprising reducing the pressure of fluid within the sleeve member to allow the at least one movable restriction member disposed within the sleeve member to move from the second position to the first position responsive to a force provided by a biasing element acting on the at least one movable restriction member. 
     
     
       18. The method of  claim 16 , wherein flowing the fluid through the sleeve member at the first flow rate below the threshold flow rate comprises flowing the fluid through the sleeve member at a flow rate below about 900 gallons (3406.8 liters) per minute. 
     
     
       19. The method of  claim 18 , wherein the threshold flow rate is between about 900 gallons (3406.8 liters) per minute and about 1200 gallons (4542.4 liters) per minute. 
     
     
       20. The method of  claim 19 , further comprising reaming a borehole using the downhole tool while the at least one movable body of the downhole tool is in the activated position.